1. Field of the Invention
The present invention relates to a card-type semiconductor device such as an IC card.
2. Description of the Related Art
Card-type semiconductor devices with a semiconductor chip built in, called IC card, are being developed actively these years.
An example of the structure of such a card-type semiconductor device is shown in FIG. 5. Reference numeral 21 denotes a wiring substrate, which has a desired wiring layer formed on one side (the upper face in the drawing) of an insulating substrate and a wiring layer to be an external connection terminal on the other side (the lower face in the drawing). Both wiring layers are electrically connected through conductive holes (not shown). A semiconductor chip 22 is mounted onto the upper face of the wiring substrate 21 with an insulating adhesive agent (mounting agent) 23, and its electrode pads are connected to the wiring layer of the wiring substrate 21 by bonding wires 24 such as gold wires. And a mold resin layer 25 of epoxy resin layer or the like is formed on the exterior of the wire-bonded portion. The resin-molded chip-mounted section is fitted into a recess of an exterior sheet 26 made of polyvinyl chloride resin, polyester resin or the like, and the wiring layer on the lower face of the wiring substrate 21 is exposed as external connection terminal.
Such a conventional card-type semiconductor device, however, could not be fabricated to have a satisfactory small thinness because the semiconductor chip 22 has a large thickness of 350 to 450 .mu.m and defines an overall thickness of the device.
The IC card is required to have a strength enough to resist against an impact, bending, twisting, etc. due to an external force. But the card-type semiconductor device, which has the above-described thick semiconductor chip 22 mounted, could not meet the requirement in terms of a bending strength and the like.